Head slider capable of being reliably released from effect of moving recording medium

ABSTRACT

A medium-opposed surface of a slider body is hemisected into first and second areas by the centerline extending in the longitudinal direction of the slider body. The second area is designed to generate a positive pressure larger than that generated at the first area when a load acting on the slider body in a direction toward a recording medium decreases. The head slider of the type is allowed to enjoy the imbalance of the lift on the slider body. This imbalance can be utilized to intentionally induce increases in the roll angle and the pitch angle of the slider body. The increase in the roll and pitch angles causes disappearance of the lift and the negative pressure generated at the medium-opposed surface. The head slider can reliably be distanced from the moving surface of the recording medium solely with the assistance of the airflow acting on the medium-opposed surface.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a recording medium drive orstorage device designed to utilize a recording medium such as a magneticrecording disk for managing information data, for example. Inparticular, the invention relates to a recording medium drive such as ahard disk drive (HDD) comprising a so-called load/unload mechanism.

[0003] 2. Description of the Prior Art

[0004] A hard disk drive (HDD) sometimes comprises a load/unloadmechanism. In general, the load/unload mechanism comprises a load barextending in the forward direction from the tip or front end of a loadbeam, and a ramp member located outside a magnetic recording disk so asto define a slope along the path of movement of the load bar. The loadbar is allowed to climb up the slope before the magnetic recording diskstops rotating. As the load bar keeps climbing, the front end of theload beam gets remoter from the surface of the rotating magneticrecording disk. When the front end of the load beam is lifted above themagnetic recording disk in this manner, a head slider is allowed to getdistanced from the surface of the rotating magnetic recording disk.

[0005] A so-called limiter is utilized to get the head slider remotefrom the surface of the rotating magnetic recording disk. The limiter isin general attached to the load beam or a gimbal actually supporting thehead slider. When the front end of the load beam is lifted to apredetermined elevation above the surface of the rotating magneticrecording disk, a part of the gimbal or load beam is engaged with thelimiter. The lift of the load bar is in this manner physically relatedto the gimbal or load beam. The gimbal or load beam is lifted so thatthe head slider is allowed to get distanced from the surface of therotating magnetic recording disk.

[0006] The limiter of the aforementioned load/unload mechanism must bemade or produced at a higher accuracy. If a space or distance is toolarge between the limiter and the gimbal or load beam, the limitercannot be engaged with the gimbal or load beam irrespective of the liftof the load beam. Accordingly, the head slider cannot be distanced fromthe surface of the magnetic recording disk.

SUMMARY OF THE INVENTION

[0007] It is accordingly an object of the present invention to provide arecording medium drive capable of reliably distancing a head slider awayfrom the surface of a recording medium when a load bar reaches apredetermined elevation above the surface of the recording medium.

[0008] According to a first aspect of the present invention, there isprovided a head slider comprising: a slider body defining amedium-opposed surface hemisected into first and second areas by thecenterline extending in the longitudinal direction of the slider body.The second area is designed to generate a positive pressure larger thana positive pressure generated at the first area when a load acting onthe slider body in a direction toward a recording medium decreases.

[0009] The head slider of the type is allowed to enjoy the imbalance ofthe lift or positive pressure on the slider body. This imbalance can beutilized to intentionally induce increases in the roll angle and thepitch angle of the slider body. The increase in the roll and pitchangles causes disappearance of the lift as well as the negative pressuregenerated at the medium-opposed surface of the slider body. The headslider in this manner can reliably be distanced from the moving surfaceof the recording medium solely with the assistance of the airflow actingon the medium-opposed surface of the slider body. Here, the pitch angleis defined as an inclined angle in the longitudinal direction of theslider body. The roll angle is defined as an inclined angle in thedirection perpendicular to the longitudinal direction of the sliderbody.

[0010] According to a second aspect of the present invention, there isprovided a recording medium drive comprising: a recording medium; a headslider opposed to the recording medium at the front end of a headsuspension; a load bar extending in the forward direction from the frontend of the head suspension; and a ramp member located outside therecording medium so as to define a slope along a path of movement of theload bar. The head slider includes a slider body defining amedium-opposed surface hemisected into first and second areas by thecenterline extending in the longitudinal direction of the slider body.In this case, the second area is designed to generate a positivepressure larger than a positive pressure generated at the first areawhen a load acting on the slider body in a direction toward therecording medium decreases. Here, the head suspension may comprise aload beam and a gimbal, for example. The combination of the load bar andthe ramp member establishes a so-called load/unload mechanism.

[0011] Now, assume that the load bar is received on the ramp memberbefore the stoppage of the recording medium. When the load bar climbs upthe slope, the load or urging force applied to the head slider from theload bar decreases. A further upward movement of the load bar along theslope causes the head slider to be substantially released from theurging force from the head suspension. At this moment, the head sliderof the type is allowed to enjoy the imbalance of the lift or positivepressure on the slider body. This imbalance can be utilized tointentionally induce increases in the roll angle and the pitch angle ofthe slider body. The increase in the roll and pitch angles causesdisappearance of the lift as well as the negative pressure generated atthe medium-opposed surface of the slider body. The head slider in thismanner can reliably be distanced from the moving surface of therecording medium, solely with the assistance of the airflow acting onthe medium-opposed surface of the slider body, without the assistance ofa so-called limiter. The head slider is allowed to reliably getdistanced from the moving surface of the recording medium when the loadbar has reached a predetermined elevation above the moving surface ofthe recording medium.

[0012] According to a third aspect of the present invention, there isprovided a head slider comprising: a slider body defining amedium-opposed surface hemisected into first and second areas by thecenterline extending in the longitudinal direction of the slider body; afront air bearing surface defined on the medium-opposed surface at aposition near the inflow end of the medium-opposed surface; and a rearair bearing surface defined on the medium-opposed surface at a positionnear the outflow end of the medium-opposed surface. The front airbearing surface is located closer to the outflow end at the second areathan at the first area.

[0013] The head slider allows generation of a lift at the front and rearair bearing surfaces. Moreover, a larger lift is in general set at thefront air bearing surface rather than the rear air bearing surface. Thehead slider is allowed to keep an attitude of a predetermined pitchangle in this manner. The front air bearing surface is located closer tothe outflow end at the second area than at the first area in the headslider, so that the influence of the airflow is relatively maintained atthe second area rather than the first area upon an increase in theelevation above the moving surface of the recording medium. This isbecause the pitch angle of the head slider allows the slider body toapproach the recording medium near the outflow end rather than theinflow end. The positive pressure is maintained at the front air bearingsurface on the second area, even though the positive pressureimmediately decreases at the front air bearing surface on the firstarea. The imbalance of the lift or positive pressure on the slider bodyin this manner can be utilized to intentionally induce increases in theroll angle and the pitch angle of the slider body. The increase in theroll and pitch angles causes disappearance of the lift as well as thenegative pressure generated at the medium-opposed surface of the sliderbody. The head slider in this manner can reliably be distanced from themoving surface of the recording medium, solely with the assistance ofthe airflow acting on the medium-opposed surface of the slider body,without the assistance of a so-called limiter.

[0014] According to a fourth aspect of the present invention, there isprovided ahead slider comprising: a slider body defining amedium-opposed surface hemisected into first and second areas by thecenterline extending in the longitudinal direction of the slider body; afront air bearing surface defined on the medium-opposed surface at aposition near the inflow end of the medium-opposed surface; and a rearair bearing surface defined on the medium-opposed surface. The rear airbearing surface is located closer to the outflow end of themedium-opposed surface than the front air bearing surface. In this case,the outflow end of the front air bearing surface is located closer tothe outflow end of the medium-opposed surface at the second area than atthe first area.

[0015] The head slider of the type is designed to keep the influence ofthe airflow relatively at the second area rather than the first areaupon an increase in the elevation in the same manner as described above,since the outflow end of the front air bearing surface is located closerto the outflow end at the second area than at the first area in the headslider. The positive pressure is maintained at the front air bearingsurface on the second area, even though the positive pressureimmediately decreases at the front air bearing surface on the firstarea. The imbalance of the lift or positive pressure on the slider bodyin this manner can be utilized to intentionally induce increases in theroll angle and the pitch angle of the slider body. The increase in theroll and pitch angles causes disappearance of the lift as well as thenegative pressure generated at the medium-opposed surface of the sliderbody. The head slider in this manner can reliably be distanced from themoving surface of the recording medium, solely with the assistance ofthe airflow acting on the medium-opposed surface of the slider body,without the assistance of a so-called limiter.

[0016] According to a fifth aspect of the present invention, there isprovided a head slider comprising: a slider body defining amedium-opposed surface hemisected into first and second areas by thecenterline extending in the longitudinal direction of the slider body; afront air bearing surface defined on the medium-opposed surface at aposition near the inflow end of the medium-opposed surface; and a rearair bearing surface defined on the medium-opposed surface. The rear airbearing surface is located closer to the outflow end of themedium-opposed surface than the front air bearing surface. The inflowend of the front air bearing surface is located closer to the outflowend of the medium-opposed surface at the second area than at the firstarea.

[0017] The head slider of the type is designed to keep the influence ofthe airflow relatively at the second area rather than the first areaupon an increase in the elevation in the same manner as described above,since the inflow end of the front air bearing surface is located closerto the outflow end at the second area than at the first area in the headslider. The positive pressure is maintained at the front air bearingsurface on the second area, even though the positive pressureimmediately decreases at the front air bearing surface on the firstarea. The imbalance of the lift or positive pressure on the slider bodyin this manner can be utilized to intentionally induce increases in theroll angle and the pitch angle of the slider body. The increase in theroll and pitch angles causes disappearance of the lift as well as thenegative pressure generated at the medium-opposed surface of the sliderbody. The head slider in this manner can reliably be distanced from themoving surface of the recording medium, solely with the assistance ofthe airflow acting on the medium-opposed surface of the slider body,without the assistance of a so-called limiter.

[0018] In any event, the aforementioned head sliders may be assembledinto a head suspension assembly, for example. The head suspensionassembly may additionally comprise a load beam and a load bar extendingin the forward direction from the front end of the load beam, forexample. The load beam and the load bar may be integral based on acommon material. A gimbal may be attached to the load beam for receivingthe head slider.

[0019] In any cases, the aforementioned head suspension assembly may beincorporated within a recording medium drive such as a hard disk drive(HDD). The recording medium drive may further comprise a recordingmedium, a ramp member located outside the recording medium so as todefine a slope along a path of movement of the load bar, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects, features and advantages of thepresent invention will become apparent from the following description ofthe preferred embodiment in conjunction with the accompanying drawings,wherein:

[0021]FIG. 1 is a plan view schematically illustrating the structure ofa hard disk drive (HDD) as a specific example of a recording mediumdrive;

[0022]FIG. 2 is an enlarged partial sectional view taken along the line2-2 in FIG. 1;

[0023]FIG. 3 is an enlarged perspective view schematically illustratinga flying head slider according to a specific example;

[0024]FIG. 4 is a plan view of a medium-opposed surface or bottomsurface for schematically illustrating the location of a front airbearing surface (ABS);

[0025]FIG. 5 is a plan view of the medium-opposed surface forschematically illustrating movements of the center of the distributionfor positive and negative pressures on the flying head slider accordingto the embodiment;

[0026]FIG. 6 is a plan view of a medium-opposed surface or bottomsurface for schematically illustrating movements of the center of thedistribution for positive and negative pressures on a flying head slideraccording to a comparative example;

[0027]FIG. 7 is a graph illustrating changes in the roll angles of theflying head sliders in response to a decrease in a load or urging forcefrom a load beam;

[0028]FIG. 8 is a graph illustrating changes in the pitch angles of theflying head sliders in response to a decrease in a load or urging forcefrom the load beam;

[0029]FIG. 9 is a graph illustrating changes in the positive pressuresof the flying head sliders in response to a decrease in a load or urgingforce from the load beam; and

[0030]FIG. 10 is a graph illustrating changes in the negative pressuresof the flying head sliders in response to a decrease in a load or urgingforce from the load beam.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0031]FIG. 1 schematically illustrates the inner structure of a harddisk drive (HDD) 11 as an example of a magnetic recording medium driveor storage device. The HDD 11 includes a box-shaped main enclosure 12defining an inner space of a flat parallelepiped, for example. At leastone magnetic recording disk 13 is mounted on the driving shaft of aspindle motor 14 within the main enclosure 12. The spindle motor 14 isallowed to drive the magnetic recording disk 13 for rotation at a higherrevolution speed such as 4,200 rpm, 5,400 rpm, 7,200 rpm, 10,000 rpm, orthe like, for example. A cover, not shown, is coupled to the mainenclosure 12 so as to define the closed inner space between the mainenclosure 12 and the cover itself.

[0032] A head actuator 15 is also accommodated in the inner space of themain enclosure 12. The head actuator 15 is coupled to a vertical supportshaft 16 for relative rotation. The head actuator 15 comprises actuatorarms 17 extending in the horizontal direction from the vertical supportshaft 16, and head suspension assemblies 18 respectively attached to thetip ends of the actuator arms 17 so as to extend in the forwarddirection from the actuator arms 17. The actuator arms 17 are related tothe front and back surfaces of the magnetic recording disk 13.

[0033] The head suspension assembly 18 comprises a load beam 19. Theload beam 19 is connected to the front or tip end of the actuator arm 17through a so-called elastic bend section. The elastic bend sectionestablishes an elasticity urging the front or tip end of the load beam19 toward the surface of the magnetic recording disk 13. A flying headslider 21 is supported on the front end of the load beam 19. The flyinghead slider 21 is received on a gimbal, not shown, attached to the loadbeam 19. The gimbal serves to allow the flying head slider 21 to changeits attitude.

[0034] As is apparent from FIG. 1, the actuator arm 17 is positioned ata predetermined inoperative or unload position when the magneticrecording disk 13 stands still. When the actuator arm 21 takes theinoperative position, the actuator arm 21 brings the tip end of the headsuspension assembly 18 outside the outer periphery of the magneticrecording disk 13. The actuator arm 17 is allowed to swing about thesupport shaft 16 from the inoperative position. When the actuator arm 17swings about the support shaft 16, the tip end of the head suspensionassembly 18 moves in the radial direction of the magnetic recording disk13 across the data zone between the outermost recording track and theinnermost recording track. Any driving power source. 22 such as a voicecoil motor (VCM) may be utilized to realize the swinging movement of theactuator arm 17.

[0035] When the magnetic recording disk 13 rotates, the flying headslider 21 is allowed to receive airflow generated along the rotatingmagnetic recording disk 13. The airflow serves to generate a positivepressure or lift and a negative pressure on the flying head slider 21,as described later in detail. The flying head slider 21 is thus allowedto keep flying above the surface of the magnetic recording disk 13during the rotation of the magnetic recording disk 13 at a higherstability established by the balance between the urging force of theload beam 19 and the lift as well as the negative pressure. When theactuator arm 17 is driven to swing in the aforementioned manner duringthe flight of the flying head slider 21, the flying head slider 21 canbe positioned right above a target recording track on the magneticrecording disk 13. When the actuator arm 17 is positioned at theinoperative position, the flying head slider 21 reaches a positionoutside the magnetic recording disk 13 beyond the outermost recordingtrack.

[0036] A load bar 23 is attached to the front end of the individual loadbeam 19. The load bar 23 further extends in the forward direction fromthe load beam 19. The load bar 23 is allowed to move in the radialdirection of the magnetic recording disk 13 based on the swingingmovement of the actuator arm 17. A ramp member 24 is located outside themagnetic recording disk 13 on the path of movement of the load bars 23.When the actuator arms 17 are positioned at the inoperative position,the load bars 23 are received on the ramp member 24. The combination ofthe load bars 23 and the ramp member 24 establishes a so-calledload/unload mechanism.

[0037] As shown in FIG. 2, the ramp member 24 includes an attachmentbase, not shown, screwed on the bottom plate of the main enclosure 12.Arm members 25 extend from the attachment base in the horizontaldirection toward the rotation axis of the magnetic recording disk 13 inthe ramp member 24. A pair of ramps 26 are integrally formed on theindividual arm member 25. The ramps 26 are designed to face the marginalzones outside the outermost recording tracks over the front and backsurfaces of the magnetic recording disk 13. A slope 27 is defined on theindividual ramp 26. The slope 27 is designed to get remote from thesurface of the magnetic recording disk 13 at the outer location in theradial direction of the magnetic recording disk 13. The slope 27 ispositioned on the path of movement of the load bar 23.

[0038] Now, assume that the magnetic recording disk 13 stops rotating.When read/write operations have been completed, the driving power source22 drives the actuator arm 17 in a normal direction toward theinoperative position. When the flying head slider 21 gets opposed to themarginal or landing zone outside the outermost recording track, the loadbar 23 is allowed to contact the slope 27 of the ramp 26. A furtherswinging movement of the actuator arm 17 allows the load bar 23 to climbup the slope 27. As the load bar 23 climbs the slope 31, the flying headslider 21 gets remote from the surface of the magnetic recording disk13. The load bar 23 is in this manner received on the ramp member 24.When the actuator arm 17 has reached the inoperative position, the loadbar 23 is received in a depression 28 on the ramp member 24. Themagnetic recording disk 13 then stops rotating. Since the load bar 23 isreliably held on the ramp member 24, the flying head slider 21 isprevented from colliding or contacting against the magnetic recordingdisk 13 even without any airflow acting on the flying head slider 21.

[0039] When the HDD 11 receives instructions to read or write magneticinformation, the magnetic recording disk 13 starts to rotate. Thedriving power source 22 drives the actuator arm 17 in the reservedirection opposite to the aforementioned normal direction after therotation of the magnetic recording disk 13 has entered the steadycondition. The load bar 23 is allowed to move out of the depression 28toward the slope 27. A further swinging movement of the actuator arm 17causes the load bar 23 to move down the slope 27.

[0040] During the downward movement of the load bar 23, the flying headslider 21 gets opposed to the surface of the rotating magnetic recordingdisk 13. Airflow generated along the surface of the rotating magneticrecording disk 13 induces a lift on the flying head slider 21. A furtherswinging movement of the actuator arm 17 allows the load bar 23 to takeoff from the slope 27 or ramp member 24. Since the magnetic recordingdisk 13 rotates in the steady condition, the flying head slider 21 canfly above the surface of the magnetic recording disk 13 without asupport of the ramp member 24.

[0041]FIG. 3 illustrates a specific example of the flying head slider 21in detail according to an example of the present invention. The flyinghead slider 21 includes a slider body 31 of a flat parallelepiped, forexample. The slider body 31 is designed to oppose a medium-opposedsurface or bottom surface to the magnetic recording disk 13. A flat basesurface 32 or reference surface is defined on the medium-opposedsurface. When the magnetic recording disk 13 rotates, airflow 33 passesalong the bottom surface from the front or leading end to the rear ortrailing end of the slider body 31. The slider body 31 includes a base,made of Al₂O₃—TiC, and Al₂O₃ (alumina) film layered over the trailing oroutflow end surface of the base. Note that the terms “leading” and“trailing” are defined based on the direction of the airflow 33.

[0042] A front rail 34 is formed to stand on the base surface 32 of theslider body 31 near the leading or inflow end of the slider body 31. Theterm “inflow” is defined based on the direction of the airflow 33 in thesame manner as described above. The front rail 34 is designed to extendin the lateral direction of the slider body 31 in parallel with theleading end of the slider body 31. The term “lateral” is defined in thedirection perpendicular to the direction of the airflow 33. The heightor thickness of the front rail 34 from the base surface 32 may be setapproximately at 1.5-2.0 μm, for example.

[0043] Likewise, a pair of rear rails 35 a, 35 b are formed to stand onthe base surface 32 of the bottom surface 26 near the trailing oroutflow end of the slider body 31. The term “outflow” is likewisedefined based on the direction of the airflow 33. The rear rails 35 a,35 b are arranged in a row in the lateral direction so as to define anairflow passage for the airflow 33 there between. The rear rails 35 a,35 b are designed to extend downstream in the rearward direction towardthe trailing end of the slider body 31. The height or thickness of therespective rear rails 35 a, 35 b from the base surface 32 may be set ata predetermined height equal to the aforementioned height of the frontrail 34.

[0044] A pair of front air bearing surfaces (ABSs) 36 a, 36 b aredefined on the top surface of the front rail 34. The front air bearingsurfaces 36 a, 36 b are designed to extend in the lateral direction ofthe slider body 31. Steps 37 are defined on the top surface of the frontrail 34 at the leading or inflow ends of the individual front airbearing surfaces 36 a, 36 b. The steps 37 serve to define a lower levelsurface 38 extending over the top surface of the front rail 34 at alevel lower than the front air bearing surfaces 36 a, 36 b. During therotation of the magnetic recording disk 13, the airflow 33 generatedalong the surface of the magnetic recording disk 13 is allowed to flowalong the lower level surface 38, the steps 37 and the front air bearingsurfaces 36 a, 36 b in this sequence. The steps 37 enable generation ofa larger positive pressure or lift on the front air bearing surfaces 36a, 36 b.

[0045] First and second rear air bearing surfaces 39 a, 39 b arerespectively defined on the top surfaces of the rear rails 35 a, 35 b. Astep 41 is defined on the top surface of the rear rail 35 a at theleading or inflow end of the first rear air bearing surface 39 a.Likewise, a step 42 is defined on the top surface of the rear rail 35 bat the leading or inflow end of the second rear air bearing surface 39b. The steps 41, 42 serve to define lower level surfaces 43, 44extending over the top surfaces of the rear rails 35 a, 35 b,respectively, at a level lower than the first and second rear airbearing surfaces 39 a, 39 b. During the rotation of the magneticrecording disk 13, the airflow 33 generated along the surface of themagnetic recording disk 13 is allowed to flow along the lower levelsurfaces 43, 44, the steps 41, 42 and the first and second rear airbearing surfaces 39 a, 39 b in this sequence. The steps 41, 42 enablegeneration of a larger positive pressure or lift on the first and secondair bearing surfaces 39 a, 39 b, respectively.

[0046] A pair of side rails 45 are formed to stand on the base surface32 of the slider body 31. The respective side rails 45 are connected tothe front rail 34 at its opposite ends in the lateral direction of theslider body 31. The respective side rails 45 are designed to extendtoward the trailing end of the slider body 31 from the opposite ends ofthe front rail 34. Airflow tends to flow around the opposite ends of thefront rail 34 after colliding against the front rail 34 when the sliderbody 31 receives the airflow at the bottom surface during the rotationof the magnetic recording disk 13. The side rails 45 prevents theairflow from entering a space behind the front rail 34 even when theairflow flows around the opposite ends of the front rail 34. The airflow33 flowing across the front rail 34 is thus easily expanded in thevertical direction upright to the surface of the magnetic recording disk13. The expansion of the airflow 33 serves to generate a negativepressure behind the front rail 34. The aforementioned lift at the airbearing surfaces 36 a, 36 b, 39 a, 39 b is balanced with the negativepressure so as to set the flying height of the flying head slider 21above the surface of the magnetic recording disk 13. Recesses 46 aredefined between the side rails 45 and the corresponding rear rails 35 a,35 b, respectively. The recesses 46 serve to introduce the airflowhaving flowed around the opposite ends of the front rail 34 into a spacebetween the rear rails 35 a, 35 b. The side rails 45 define the topsurfaces, respectively, leveled or flush with the lower level surface 38on the front rail 34.

[0047] A read/write head element 47 is mounted on the slider body 31.The read/write head element 47 is embedded in the alumina film of theslider body 31. Read and write gaps of the read/write head element 47are allowed to get exposed at the first rear air bearing surface 39 a.The read/write head element 47 may include a write element such as athin film magnetic head utilizing a thin film coil pattern, for example,and a read element such as a giant magnetoresistive (GMR) element, atunnel-junction magnetoresistive (TMR) element, or the like.

[0048] The flying head slider 21 of this type allows generation of alarger positive pressure or lift on the front air bearing surface 36 a,36 b rather than the first and second rear air bearing surfaces 39 a, 39b. When the slider body 31 flies above the surface of the magneticrecording disk 13, the slider body 31 is kept in an inclined attitude ofpitch angle α. The pitch angle α is defined as an inclined angle in thedirection of the airflow 33, namely, in the longitudinal direction ofthe slider body 31. The pitch angles α serves to minimize the distancebetween the trailing end of the slider body 31 and the surface of themagnetic recording disk 13 near the outflow end rather than the inflowend of the slider body 31.

[0049] As is apparent from FIG. 3, adsorption preventing protrusions(pads) 48 are formed on the front rail 34, the rear rail 35 b, and thelike. The adsorption preventing protrusions 48 are designed to stand onthe lower level surfaces 38, 44 and the like. The adsorption preventingprotrusions 48 define the tip ends, respectively, located above thelevel of the front air bearing surfaces 36 a, 36 b as well as the firstand second rear air bearing surfaces 39 a, 39 b. The absorptionpreventing protrusions 48 serve to prevent the front air bearingsurfaces 36 a, 36 b and the first and second rear air bearing surfaces39 a, 39 b from contacting the surface of the magnetic recording disk13, even if the flying head slider 21 falls on the surface of themagnetic recording disk 13. A contact area is minimized between theslider body 31 and the magnetic recording disk 13. The slider body 31 isprevented from receiving an adsorption or meniscus effect acting from alubricating agent or oil spreading over the surface of the magneticrecording disk 13.

[0050] As is apparent from FIG. 4, the medium-opposed surface or bottomsurface is hemisected into first and second areas 52 a, 52 b by thecenterline 51 extending in the longitudinal direction of the slider body31. The inflow end of the front air bearing surface 36 a on the secondarea 52 b is located closer to the outflow end of the bottom surface ascompared with the inflow end of the front air bearing surface 36 b onthe first area 52 a. Likewise, the outflow end of the front air bearingsurface 36 a on the second area 52 b is located closer to the outflowend of the bottom surface as compared with the outflow end of the frontair bearing surface 36 b on the first area 52 a. In this manner, thefront air bearing surface 36 a on the second area 52 b is totallylocated closer to the outflow end of the slider body 31 rather than thefront air bearing surface 36 b on the first area 52 a. The front airbearing surfaces 36 a, 36 b asymmetric in this manner serve to establishat the second area 52 b over the bottom surface of the slider body 31 apositive pressure larger than the positive pressure generated at thefirst area 52 a when a load or the urging force acting on the sliderbody 31 from the load beam 19 in the direction toward the magneticrecording disk 13 decreases.

[0051] Here, the centerline 51 may coincide with the axis of symmetry ofthe rectangular base surface 32, for example. Alternatively, thecenterline 51 may simultaneously pass through the middle of the inflowend and the middle of the outflow end of the slider body 31. Asillustrated, the first rear air bearing surface 39 a exposing theread/write head element 47 may be located on the second area 52 b.Alternatively, the first rear air bearing surface 39 a may be located onthe first area 52 a.

[0052] Now, assume that the load bar 23 is received on the ramp member24 before the rotation of the magnetic recording disk 13 is terminated.When the load bar 23 climbs up the slope 27, the load or urging forceapplied to the flying head slider 21 from the load bar 23 decreases. Afurther upward movement of the load bar 23 along the slope 27 causes aso-called dimple or domed protrusion on the load beam 19 to getdistanced from the back of the gimbal. Since the front air bearingsurface 36 a on the second area 52 b is located closer to the outflowend of the bottom surface as compared with the front air bearing surface36 b on the first area 52 a, the influence of the airflow is relativelymaintained on the front air bearing surface 36 a on the second area 52 bupon an increase in the elevation while the front air bearing surface 36b on the first area 52 a suffers from release from the influence of theairflow. This is because the slider body 31 approaches the magneticrecording disk 13 near the outflow end rather than the inflow end basedon the pitch angle α of the flying head slider 21. The positive pressureis maintained at the front air bearing surface 36 a on the second area52 b, even though the positive pressure quickly decreases at the frontair bearing surface 36 b on the first area 52 a. The imbalance of thepositive pressure induces an increase in the roll angle and the pitchangle α. A sharp increase of the roll angle and pitch angle α in thismanner allows the flying head slider 21 to easily get distanced from themoving surface of the rotating magnetic recording disk 13 withoutassistance of a so-called limiter. The flying head slider 21 is thusallowed to get remote from the rotating magnetic recording disk 13 basedon the airflow acting on the bottom surface, so that the flying headslider 21 reliably flies away from the surface of the rotating magneticrecording disk 13 at a predetermined elevation above the surface of themagnetic recording disk 13. Here, the roll angle is defined as aninclined angle in the direction perpendicular to the direction of theairflow 33, namely, in the lateral direction of the slider body 31.

[0053] The inventors have examined the property of the aforementionedflying head slider 21. The inventors utilized a computer-basedsimulation so as to observe the distribution of the positive andnegative pressure at the bottom surface. The inventors derived themovement of the center of the distribution for the positive pressure aswell as of the center of the distribution for the negative pressure. Asshown in FIG. 5, when the load beam 19 reduced a load on the flying headslider 21, the center of the distribution of the lift or positivepressure moved on the flying head slider 21 on a path 54 extending alonga diagonal line from the center of the rectangular base surface 32. Asis apparent from a path 55, the center of the distribution of thenegative pressure hardly moved on the flying head slider 21. Theinventors have also examined the property of a flying head slier 56according to a comparative example. The flying head slider 56 wasdesigned to include the outflow end of the front air bearing surface 36a located near the inflow end of the base surface 32 as compared withthe outflow end of the front air bearing surface 36 b. It has beenconfirmed that the center of the distribution of the lift or positivepressure moved on the flying head slider 56 on a path 57 extending alongthe longitudinal centerline from the center of the rectangular basesurface 32. As is apparent from a path 58, the center of thedistribution of the negative pressure hardly moved on the flying headslider 56.

[0054] The inventors have subsequently observed changes in the rollangles of the flying head sliders 21, 56, respectively. As is apparentfrom FIG. 7, when the load bar 23 climbed up the slope 27 of the rampmember 24, the roll angle of the flying head slider 21, 56 graduallyincreased by a slight amount between a threshold A and a threshold B.When the load bar 23 reached a predetermined elevation, corresponding tothe threshold B, the dimple of the load beam 19 lost contact with theback of the gimbal. After this moment, the roll angle of the flying headslider 21 rapidly increased. On the other hand, an increase in the rollangle of the flying head slider 56 of the comparative example wassuppressed within a smaller range. It has been confirmed that theaforementioned asymmetric distribution of the lift or positive pressureduring the decrease of a load from the load beam 19 induces a rapidincrease in the roll angle of the flying head slider 21.

[0055] The inventors have also observed changes in the pitch angles ofthe flying head sliders 21, 56, respectively. As is apparent from FIG.8, when the load bar 23 climbed up the slope 27 of the ramp member 24,the pitch angle of the flying head slider 21, 56 gradually increased bya slight amount between a threshold A and a threshold B. When the loadbar 23 reached the predetermined elevation, corresponding to thethreshold B, the pitch angle α of the flying head slider 21 rapidlyincreased. Although the flying head slider 56 also enjoyed an increasedpitch angle α as the load beam 19 reduced the load below the thresholdB, a sufficient increase in the pitch angle α could not be obtainedunless the load beam 19 largely decreased the load as compared with thecase of the flying head slider 21. It has been confirmed that the flyinghead slider 21 according to the invention reliably enjoys a rapidincrease in the pitch angle α along with an increase in the roll angle.

[0056] Additionally, the inventors have observed changes in the lift orpositive pressures of the flying head sliders 21, 56, respectively. Asis apparent from FIG. 9, when the load bar 23 reached the predeterminedelevation, corresponding to a threshold B, the positive pressureimmediately disappeared on the flying head slider 21. The disappearanceof the positive pressure represents a complete release of the flyinghead slider 21 from the effect of the rotating magnetic recording disk13. The flying head slider 56 of the comparative example required alarger decrease in the load from the load beam 19 until the flying headslider 56 was completely released from the effect of the rotatingmagnetic recording disk 13. In other words, the flying head slider 56cannot get distanced from the rotating magnetic recording disk 13 solelywith the effect of the airflow acting on the flying head slider 56. Theinventor shave likewise observed changes in the negative pressures ofthe flying head sliders 21, 56, respectively. As is apparent from FIG.10, when the load bar 23 reached the predetermined elevation,corresponding to a threshold B, the negative pressure immediatelydisappeared on the flying head slider 21. As is apparent from comparisonbetween FIGS. 9 and 10, it has been confirmed that the positive pressurerather than the negative pressure largely changes based on a decrease inthe load from the load beam 19.

What is claimed is:
 1. A head slider comprising: a slider body defininga medium-opposed surface hemisected into first and second areas by acenterline extending in a longitudinal direction of the slider body,wherein said second area is designed to generate a positive pressurelarger than a positive pressure generated at the first area when a loadacting on the slider body in a direction toward a recording mediumdecreases.
 2. A recording medium drive comprising: a recording medium; ahead slider opposed to the recording medium at a front end of a headsuspension; a load bar extending in a forward direction from the frontend of the head suspension; and a ramp member located outside therecording medium so as to define a slope along a path of movement of theload bar, wherein said head slider includes a slider body defining amedium-opposed surface hemisected into first and second areas by acenterline extending in a longitudinal direction of the slider body,said second area being designed to generate a positive pressure largerthan a positive pressure generated at the first area when a load actingon the slider body in a direction toward the recording medium decreases.3. A head slider comprising: a slider body defining a medium-opposedsurface hemisected into first and second areas by a centerline extendingin a longitudinal direction of the slider body; a front air bearingsurface defined on the medium-opposed surface at a position near aninflow end of the medium-opposed surface; and a rear air bearing surfacedefined on the medium-opposed surface at a position near an outflow endof the medium-opposed surface, wherein the front air bearing surface islocated closer to the outflow end at the second area than at the firstarea.
 4. A head suspension assembly comprising: a load beam; a load barextending in a forward direction from a front end of the load beam; ahead slider supported on the load beam, said head slider including aslider body defining a medium-opposed surface hemisected into first andsecond areas by a centerline extending in a longitudinal direction ofthe slider body; a front air bearing surface defined on themedium-opposed surface at a position near an inflow end of themedium-opposed surface; and a rear air bearing surface defined on themedium-opposed surface at a position near an outflow end of themedium-opposed surface, wherein the front air bearing surface is locatedcloser to the outflow end at the second area than at the first area. 5.A head slider comprising: a slider body defining a medium-opposedsurface hemisected into first and second areas by a centerline extendingin a longitudinal direction of the slider body; a front air bearingsurface defined on the medium-opposed surface at a position near aninflow end of the medium-opposed surface; and a rear air bearing surfacedefined on the medium-opposed surface, said rear air bearing surfacelocated closer to an outflow end of the medium-opposed surface than thefront air bearing surface, wherein the outflow end of the front airbearing surface is located closer to the outflow end of themedium-opposed surface at the second area than at the first area.
 6. Ahead suspension assembly comprising: a load beam; a load bar extendingin a forward direction from a front end of the load beam; a head slidersupported on the load beam, said head slider including a slider bodydefining a medium-opposed surface hemisected into first and second areasby a centerline extending in a longitudinal direction of the sliderbody; a front air bearing surface defined on the medium-opposed surfaceat a position near an inflow end of the medium-opposed surface; and arear air bearing surface defined on the medium-opposed surface, saidrear air bearing surface located closer to an outflow end of themedium-opposed surface than the front air bearing surface, wherein theoutflow end of the front air bearing surface is located closer to theoutflow end of the medium-opposed surface at the second area than at thefirst area.
 7. A head slider comprising: a slider body defining amedium-opposed surface hemisected into first and second areas by acenterline extending in a longitudinal direction of the slider body; afront air bearing surface defined on the medium-opposed surface at aposition near an inflow end of the medium-opposed surface; and a rearair bearing surface defined on the medium-opposed surface, said rear airbearing surface located closer to an outflow end of the medium-opposedsurface than the front air bearing surface, wherein the inflow end ofthe front air bearing surface is located closer to the outflow end ofthe medium-opposed surface at the second area than at the first area. 8.A head suspension assembly comprising: a load beam; a load bar extendingin a forward direction from a front end of the load beam; a head slidersupported on the load beam, said head slider including a slider bodydefining a medium-opposed surface hemisected into first and second areasby a centerline extending in a longitudinal direction of the sliderbody; a front air bearing surface defined on the medium-opposed surfaceat a position near an inflow end of the medium-opposed surface; and arear air bearing surface defined on the medium-opposed surface, saidrear air bearing surface located closer to an outflow end of themedium-opposed surface than the front air bearing surface, wherein theinflow end of the front air bearing surface is located closer to theoutflow end of the medium-opposed surface at the second area than at thefirst area.